Welcome to the forum Daynahj. Have you set up and cycled your tank yet? If so what are your water parameters? The actual parameters will help us figure out what fish are best for your water. Not all water is alike.
Angels will work just fine with cories if the tank is cycled and parameters are suitable.

Yes, angels and corys will get along fine but like it has been said angels are very tall fish and need correspondingly deep tanks to live in. They'll outgrow a 20 gallon tank for sure. I'd say keep the cories and wait for a larger tank for angels.

Did you see anything else at the store that caught your eye? There's not much that won't get along fine with corys.